Local Service for Android service backend

Service is a serviced component of the Android system for developing features that do not have a user interface and run in the background for a long time

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Service Introduction

Below I will briefly summarize the service basics into the following 6 points:

-what function does 1.Service apply to?

Service使用于无须用户干预，且有规则地运行或长期运行的后台共功能。

-Features of 2.Service

Service没有用户界面，相比于其他应用程序更加有利于降低系统资源的消耗。Service比Activity具有更高优先级，在资源紧张时，Service不会被Android系统优先终止。即使Service被系统终止，在系统资源恢复后Service也将自动回复运行状态，因此可以认为Service是在系统中可以稳定长期运行的组件。

-The usefulness of 3.Service

1.实现后台服务功能2.可用于进程间通信

-4.Service life cycle

完整的生命周期从onCreate()开始到onDestroy()结束，在onCreate()中完成Service的初始化工作，在onDestroy()中释放所有占用的资源。可以粗略的认为活动生命周期以onDestroy()标志结束。

-5. Using the service through the startup mode

• Realize

  通过Context.startService()启动Service,通过Context.stopService()停止Seivice。Context指其他组件，因此Service一定是由其它组件启动的，但停止过程可以通过其他组件或自身完成。

• Characteristics

  启动Service的组件无法获取Service的对象实例，因此也无法调用Service中的任何函数，也不能获取Service中的任何状态和数据信息。所以以启动方式的Service需要具备自管理的能力。

-6. Using the service through bindings

• Realize

  在其他组件中调用Context.bindService()建立服务连接，调用Context.unbindService()停止服务连接。如果在绑定过程中Service未启动，Context.bindService()会自动启动Service。

• Characteristics

  其他组件可以获取Service的实例对象并调用Service中的函数，可以获取Service中的状态和数据信息。同一个Service可以和被多个组件绑定服务连接，即同一个Service可以同时为多个组件服务。

Local Service

concept: Both the caller and the service of the local service are in the same program and are calls that do not require a cross-process to implement the service.
The following is a simple demo designed to a local service, including how to start and how to bind it. Main interface

Project structure

Randomservice.java (startup mode) complete code:

 PackageCom.example.servicedemo;ImportAndroid.app.Service;ImportAndroid.content.Intent;ImportAndroid.os.IBinder;Importandroid.support.annotation.Nullable;ImportAndroid.widget.Toast;/** * Created by Yinghao on 2016/5/6. * * Public  class randomservice extends Service {    / * Onstartcommand replaces OnStart but in Super.onstartcommand (intent, flags, Startid); method calls the OnStart () method (for compatibility) */< /c5>    PrivateThread Workthread;@Override     Public void onCreate() {Super. OnCreate (); Toast.maketext ( This,"Call OnCreate ()", Toast.length_short). Show (); Workthread =NewThread (NULL, BackgroundWork,"Workthread"); }@Override     Public void OnStart(Intent Intent,intStartid) {Super. OnStart (Intent, Startid); Toast.maketext (Randomservice. This,"OnStart ()", Toast.length_short). Show ();if(!workthread.isalive ())        {Workthread.start (); }    }@Override     Public int Onstartcommand(Intent Intent,intFlagsintStartid) {Toast.maketext (randomservice. This,"Onstartcommand ()", Toast.length_short). Show ();return Super. Onstartcommand (Intent, flags, Startid); }@Override     Public void OnDestroy() {Toast.maketext ( This,"Call OnDestroy ()", Toast.length_short). Show (); Workthread.interrupt ();Super. OnDestroy (); }PrivateRunnable backgroundwork =NewRunnable () {@Override         Public void Run() {Try{ while(! Thread.interrupted ()) {Doublerandomdouble = Math.random ();                    Mainactivity.updategui (randomdouble); Thread.Sleep ( +); }            }Catch(Interruptedexception e)            {E.printstacktrace (); }        }    };/** * Service is called after the function is bound to return to the service object instance * /    @Nullable    @Override     PublicIBinderOnbind(Intent Intent) {return NULL; }}

Mathservice.java (Binding method) complete code:

 PackageCom.example.servicedemo;ImportAndroid.app.Service;ImportAndroid.content.Intent;ImportAndroid.os.Binder;ImportAndroid.os.IBinder;Importandroid.support.annotation.Nullable;ImportAndroid.widget.Toast;/** * Created by Yinghao on 2016/5/6. * * Public  class mathservice extends Service {    /** * Use this service to obtain a service instance in a binding form */    Private FinalIBinder Mbinder =NewLocalbinder (); Public  classlocalbinder extends Binder{  MathService GetService () {returnMathService. This; }    }@Nullable    @Override     PublicIBinderOnbind(Intent Intent) {Toast.maketext (MathService). This,"Local bindings", Toast.length_short). Show ();returnMbinder; }@Override     Public Boolean Onunbind(Intent Intent) {Toast.maketext (MathService). This,"Cancel local bindings: MathService", Toast.length_short). Show ();return Super. Onunbind (Intent); } Public Long Add(LongALongb) {returnA + b; }}

Mainactivity.java Complete code:

 PackageCom.example.servicedemo;ImportAndroid.content.ComponentName;ImportAndroid.content.Context;ImportAndroid.content.Intent;ImportAndroid.content.ServiceConnection;ImportAndroid.os.Handler;ImportAndroid.os.IBinder;Importandroid.support.v7.app.AppCompatActivity;ImportAndroid.os.Bundle;ImportAndroid.view.View;ImportAndroid.widget.Button;ImportAndroid.widget.TextView;ImportCOM.EXAMPLE.SIMPLERANDOMSERVICEDEMO.R; Public  class mainactivity extends appcompatactivity {    PrivateButton Mstartbutton;PrivateButton Mstopbutton;Private StaticTextView Mlabeltextvie;Private StaticHandler Handler =NewHandler ();Private Static DoubleRandom/** * Handler The Runnable object is passed to the interface thread's queue * so that it can update the UI */     Public Static void Updategui(Doublerefreshdouble) {random = refreshdouble;    Handler.post (refreshlable); } Public StaticRunnable refreshlable =NewRunnable () {@Override         Public void Run() {Mlabeltextvie.settext (string.valueof (random)); }    };PrivateMathService MathService;Private BooleanIsbound =false;PrivateTextView sum;PrivateButton Bindbutton;PrivateButton Unbindbutton;PrivateButton AddButton;@Override    protected void onCreate(Bundle savedinstancestate) {Super. OnCreate (Savedinstancestate); Setcontentview (R.layout.activity_main);/** * Handler * *        FinalIntent Intent =NewIntent ( This, Randomservice.class);        Mstartbutton = (Button) Findviewbyid (R.id.start);        Mstopbutton = (Button) Findviewbyid (r.id.stop);        Mlabeltextvie = (TextView) Findviewbyid (R.id.tv_label); Mstartbutton.setonclicklistener (NewView.onclicklistener () {@Override             Public void OnClick(View v)            {StartService (intent);        }        }); Mstopbutton.setonclicklistener (NewView.onclicklistener () {@Override             Public void OnClick(View v)            {StopService (intent); }        });/** * Bind Service * /sum = (TextView) Findviewbyid (R.id.tv_result);         Bindbutton = (Button) Findviewbyid (R.id.bind);         Unbindbutton = (Button) Findviewbyid (R.id.unbind); AddButton = (Button) Findviewbyid (R.id.add);FinalIntent serviceintent =NewIntent (mainactivity. This, Mathservice.class); Bindbutton.setonclicklistener (NewView.onclicklistener () {@Override             Public void OnClick(View v) {if(!isbound)                    {Bindservice (serviceintent, mconnection, context.bind_auto_create); Isbound =true;        }            }        }); Unbindbutton.setonclicklistener (NewView.onclicklistener () {@Override             Public void OnClick(View v) {if(Isbound) {Unbindservice (mconnection);//If you change the above unbind to the following shutdown service, you will not be able to bind successfully again//StopService (serviceintent);MathService =NULL; Isbound =false;        }            }        }); Addbutton.setonclicklistener (NewView.onclicklistener () {@Override             Public void OnClick(View v) {if(MathService = =NULL) {Sum.settext ("Unbound Service");return; }LongA = Math.Round (Math.random () * -);Longb = Math.Round (Math.random () * -);Longresult = Mathservice.add (A, b); String msg = string.valueof (a) +"+"+string.valueof (b) +"="+result;            Sum.settext (msg);    }        }); }PrivateServiceconnection mconnection =NewServiceconnection () {@Override         Public void onserviceconnected(componentname name, IBinder service)        {MathService = ((mathservice.localbinder) service). GetService (); }@Override         Public void onservicedisconnected(componentname name) {MathService =NULL; }    };}

Local Service for Android service backend